Microsoft Graph - List apps in chat - 404 UnknownError

Hello @Benjiiim -Listing installed apps in a chat (GET /chats/{chat-id}/installedApps) works for group chats and 1:1 chats. For meeting chats (chats created for online meetings), this API is not fully supported for all tenants and scenarios. The 404 error with UnknownError is a common symptom when the API is not supported for the chat type or the app context.

Meeting chats are a special type of chat in Teams, and the Graph API support for listing or adding apps to these chats is limited and sometimes only available for certain Microsoft-internal or preview tenants.

There is no supported workaround to list or add apps to a meeting chat via Microsoft Graph in most production/dev tenants.If you need to automate app installation for meetings, this is not currently possible via Graph API.